Grease manufacture



G. KAUFMAN GREASE MANUFACTURE Feb. 15, 1938,

Filed June '7, 1935 Gas Kaufman INVENTOR I f UNITED STATES 'Patented Feb. 15, 193s GREASE MANUFACTURE Gus Kaufman, Beacon, N. Y., assignor The Texas Company, New York, N. Y., a corporation of Delaware Application June 7, 1935, Serial No. v25,361

s claims.'

This invention relates to the manufacture of grease.

An object of the present invention is to increase the hardness of a soda base grease without increase in the soap content thereof.

It has heretofore been suggested to pass grease through a. milling machine of the character of a burr stone mill, to work down or reduce the hardness of the grease and minimize lumpiness.

As distinguished from the working down or reduction in hardness resulting from passing grease throughsuch a burr stone mill, I have discovered that when greases of the soda base type are passed through a colloid mill, a definite increase in hardness of the grease results, which is the opposite of what would be expected.

In accordance with the present invention, a soda base grease is passed in a thin iilm between highly rotating closely spaced surfaces where it is thrown outwardly by centrifugal force while being subjected to a powerful shearing action, to thereby give a substantial increase in hardness of the grease, generally expressed as a decrease in consistency or a reduction in A. S. T. M. penetration of the grease. 'This is preferably accomplished by passing the grease between oppositely rotating discs of a colloid mill. Any suitable type of conventional colloid mill of this character may be employed. The grease may be heated to render it suiiiciently fluid for pumping, and is passed in heated condition through the mill. Ordinarily, a single passage through a high speed colloid mill having discs rotating in opposite directions at a speed of around 2000-5000 R. P. M., will give a very substantial decrease in A. S. T. M. penetration. If desired, the grease can be recirculated through the mill until a desired penetration is obtained.. As a result of this procedure, greases can be made of specied consistencies with lower soap content, thereby reducing the cost as a result of substituting the cheaper mineral oil constituent for the more expensive soap constituent. In addition, this procedure insures the elimination of soap lumps and gives a more uniform product.

Referring to the attachedl drawing, which illustrates a preferred embodiment of apparatus for practicing the method of this invention, a suitable soda base grease is maintained in a heated condition in vat Ill provided with steam jacket II. I'he grease, which is suiliciently fluid for pumping, is withdrawn from vat I0 through line I2 by charge pump I3 and delivered through line Il, hollow shaft I5 and a centrally arranged opening in disc I6 of a colloid mill. Line I4 is connected with the rotary hollow shaft I5 by a suitable coupling and stufling box I8.

'I'he type of colloid mill illustrated is that known as the U. S. -colloid mill, although any suitable conventional mill of this character can be em- (ci. s'z-s) ployed. .This mill comprises two oppositely rotating discs I6 and 2|l,`mounted on shafts I5 and 2| respectively, which are positively driven in opposite directions by motors 22'and 23 respectively, through shafts 22' and 23' and gearing 24 and 25. The discs are enclosed within a suitable casing 26. Peripheral edges of discs I6 and 20 are set very close together by proper adjustment of shaft 2| by means of screw 2|', so that the grease is subjected to a high shearing force as it is thrown outwardly between the discs by centrifugal force.

The grease discharged from the peripheries of the discs is caught within casing 26, from where it is discharged by pipe 21 into reservoir 28. In case it is desired to pass the grease a plural number of times through the mill, this may be accomplished by recirculating the grease from the reservoir 2B through line 29 by pump 30, which delivers it through line 3| to the Vat I0.

As a specific example, a U. S. colloid mill equipped with two steel discs of 6" diameter each, and driven in opposite directions by 3 H. P. motors at 3500 R. P. M., was employed. A soda base grease of the type adapted for automotive lubrication, and having the following approximate composition:

Percent Cylinder stock (S. U. vis. 185-195/210 F.) 95.5 Sodium soap of hard tallow 4.0 Water 0.5

was passed once through the above colloid mill. The grease had an initial A. S. T. M. penetration of 438, while after treatment the A. S. T. M. penetration was 352.

A similar type of soda base grease having the following approximate composition:

. Percent Cylinder stock (S. U. vis. l60-1'70/210" F.) 89.5 Sodium soap of hard tallow 10.0 Water 0.5

was reduced from an initial A. S. T. M. penetration of 340 to an `A. S. T. M. penetration of 238 by one through passage in the above mill.

A soda base grease of the type of a sponge grease adapted for use von shaft bearings, and having the following approximate composition:

Percent Distillate mineral lubricating oil (S. U. vis.

180/100 F.) 84.5 Sodium soap oi hard tallow 14.0 Water 1.5

being subjected to a shearing action, with re` sultant substantial decrease in the A. S. T. M.- penetration of the grease, and then passing the greasev without further treatment to a zone of collection for packaging for use.

2. The method oi increasing the hardnessjof a soda base grease of ilbrous texture and water content not substantially in excess of about 1.5%, without increasing the soap content, which comprises, after completing the operations of saponifying the fat and mixing with mineral oil to form a homogeneous grease. heating the homogeneous grease until fluid, pumping the iluid grease in a thin film through closely spaced positively driven high speed oppositely rotating smooth surfaces where it is thrown outwardly by centrifugal force vwhile being subjected to a shearing action, with resultant substantial decrease in the A. S. T. M. penetration of the grease, and then passing the grease without further treatment to a zone of collection for packaging for use.

3. "nie method of claim 2, in which the grease is recirculated from the zone of collection back to thel heating zone and then through the rotating surfaces until a desired decrease in A. S. T. M. penetration is obtained.

Gus KAUF'MAN.r 2,0 

